A frequent requirement is to read or write data to memory cards. Each time a memory card is accessed; there is a risk of data corruption if the connection to the card is unexpectedly interrupted mid-process. For this reason it has been common to detect the presence of a card either by a “card detect” signal using one of the card's own contact pads or a switch mechanically activated by the card.
Both of these methods have the weakness of only being able to indicate a “card detect” status, and that detect range will extend over a certain distance. The card can be moving while the detect status is valid. This is a poor indicator to the control electronics performing the read and write operations on the memory card, and there is a risk of data corruption.
To Attempt to solve this unsatisfactory situation a solution has been devised in U.S. 6,488,528 patent where a switch senses that the card is physically seated and locked in the reader by a tab, which locates into a cut-out formed in the card. In practice a reader using U.S. 6,488,528 patent cannot work with all memory cards. Card types such as Smart Media and Smartcards do not contain any cut-outs into which a tab can locate, so they can not be locked. Furthermore, an undesirable situation arises where a user tries to pull out a locked card: The user has no knowledge of the locking function; as it is unseen and internal to the device, this can easily result in damage.
The present invention overcomes these deficiencies and weaknesses by allowing the controlling electronics to only perform the read and write operations on the memory card when the memory card is fully seated and at rest, thereby eliminating the possibility of data corruption due to unexpected card disconnection. The user can only extract the memory card by use of the push button.
Since the invention does not make use of any card cut-out feature its use is applicable to all memory card types.